[NETPOLL]: Fixups for 'fix soft lockup when removing module'

>From my recent patch:

> >    #1
> >    Until kernel ver. 2.6.21 (including) cancel_rearming_delayed_work()
> >    required a work function should always (unconditionally) rearm with
> >    delay > 0 - otherwise it would endlessly loop. This patch replaces
> >    this function with cancel_delayed_work(). Later kernel versions don't
> >    require this, so here it's only for uniformity.

But Oleg Nesterov <oleg@tv-sign.ru> found:

> But 2.6.22 doesn't need this change, why it was merged?
> 
> In fact, I suspect this change adds a race,
...

His description was right (thanks), so this patch reverts #1.

Signed-off-by: Jarek Poplawski <jarkao2@o2.pl>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/core/netpoll.c

@@ -72,8 +72,7 @@ static void queue_process(struct work_struct *work)
 			netif_tx_unlock(dev);
 			local_irq_restore(flags);
 
-			if (atomic_read(&npinfo->refcnt))
-				schedule_delayed_work(&npinfo->tx_work, HZ/10);
+			schedule_delayed_work(&npinfo->tx_work, HZ/10);
 			return;
 		}
 		netif_tx_unlock(dev);
@@ -786,8 +785,7 @@ void netpoll_cleanup(struct netpoll *np)
 			if (atomic_dec_and_test(&npinfo->refcnt)) {
 				skb_queue_purge(&npinfo->arp_tx);
 				skb_queue_purge(&npinfo->txq);
-				cancel_delayed_work(&npinfo->tx_work);
-				flush_scheduled_work();
+				cancel_rearming_delayed_work(&npinfo->tx_work);
 
 				/* clean after last, unfinished work */
 				if (!skb_queue_empty(&npinfo->txq)) {